Steel rivets work by being inserted into aligned holes in two or more materials, and then being deformed to create a permanent mechanical fastener. This deformation, usually achieved through hammering or a rivet gun, expands the rivet's tail (the part protruding through the materials) to more than its original diameter, effectively clamping the materials together.
Here's a breakdown of the process:
- Preparation: Holes are drilled or punched through the materials being joined. The holes must be aligned for the rivet to pass through.
- Insertion: The rivet, consisting of a smooth cylindrical shaft with a head on one end, is inserted through the aligned holes.
- Upsetting/Bucking: The tail of the rivet, protruding beyond the materials, is then deformed. This is typically done using a hammer and bucking bar or a pneumatic rivet gun.
- Hammering: A bucking bar (a heavy, smooth metal block) is held firmly against the head of the rivet. The tail is then hammered, causing it to flatten and widen.
- Rivet Gun: A rivet gun uses compressed air to rapidly and repeatedly strike the rivet tail, deforming it in a controlled manner.
- Formation of the Second Head: The upsetting process creates a second, deformed head on the tail of the rivet. This new head, along with the original head, clamps the materials tightly together. The expanded tail, now much larger than the original hole, prevents the rivet from backing out.
- Finished Joint: The result is a strong, permanent joint. The rivet fills the hole tightly, resisting shear forces and preventing slippage between the joined materials.
Key Aspects of Rivet Functionality:
- Mechanical Fastening: Rivets create a purely mechanical bond, relying on friction and physical deformation, unlike welding which creates a metallurgical bond.
- Shear Strength: Rivets excel at resisting shear forces (forces acting parallel to the fastener's axis).
- Tensile Strength: While not as strong in tension as some other fasteners like bolts, rivets still provide adequate tensile strength for many applications.
- Permanent Joint: Rivets generally create permanent joints that cannot be easily disassembled without damaging the rivet or the joined materials.
- Material Compatibility: Steel rivets are typically used to join steel or other compatible metals. The rivet material should be selected to avoid galvanic corrosion with the joined materials.
In summary, steel rivets provide a robust and reliable method for creating permanent mechanical joints by deforming the rivet tail to clamp materials tightly together.
